Many researchers believe that Earth’s early oceans were very hot, reaching 80̊ Celsius, and that life originated in these conditions. New findings may prove the opposite to be true. Harald Furnes, Professor Emeritus at the Department of Earth Science, has analysed volcanic and sedimentary rocks in the Barberton Greenstone Belt, South Africa. The volcanic rocks were deposited at depths of 2 to 4 kilometres.
“We have found evidence that the climate 3.5 billion years ago was a cold environment,” says Furnes.
Furnes thinks some researchers may have difficulties accepting the new knowledge of an early, cold Earth. A paradigm shift in Earth Science is not to be expected, but he thinks the climate of the early earth will be seen in a new light. More.
Well, it’s a horseshoe in the works for the early evolution of life.
See also: Ice cube life on frozen Earth “Alternatively, life could have still formed in hot conditions, around hydrothermal vents within those cold waters. There’s no obvious way to work out which of the competing ideas is correct.”
Maybe if we throw enough models at the origin of life… some of them will stick?
What we know and don’t, know about the origin of life
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Here’s the abstract:
Estimates of ocean temperatures on Earth 3.5 billion years ago (Ga) range between 26̊ and 85̊C. We present new data from 3.47- to 3.43-Ga volcanic rocks and cherts in South Africa suggesting that these temperatures reflect mixing of hot hydrothermal fluids with cold marine and terrestrial waters. We describe fossil hydrothermal pipes that formed at ~200̊C on the sea floor >2 km below sea level. This ocean floor was uplifted tectonically to sea level where a subaerial hydrothermal system was active at 30̊ to 270̊C. We also describe shallow-water glacial diamictites and diagenetic sulfate mineral growth in abyssal muds. These new observations reveal that both hydrothermal systems operated in relatively cold environments and that Earth’s surface temperatures in the early Archean were similar to those in more recent times. (public access) – M. J. de Wit, H. Furnes. 3.5-Ga hydrothermal fields and diamictites in the Barberton Greenstone Belt–Paleoarchean crust in cold environments. Science Advances, 2016; 2 (2): e1500368 DOI: 10.1126/sciadv.1500368
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